Social media addiction in university students in Lebanon and its effect on student performance.

Objective: This study aims to assess addiction to social media among university students and to explore the association of addiction to social media with academic performance. Methods: A random sample of 997 university students filled in a self-administered questionnaire using Google form (response rate 81%). The questionnaire adopted a validated scale (Social Media Addiction Scale, SMAS) and included questions about socio-demographics. Grade point average, absences, and passing rate were extracted for each student from the university management system. Results: Results showed that each of the three dimensions of addiction to social media (compulsive feelings, social consequences and time displacement) reduce at least one indicator of academic performance (GPA, absenteeism and passing rate). Conclusion: Results call to design and evaluate interventions that tackle different social media addiction dimensions to reduce their negative impact on academic performance.

Cannabinoids and Myocardial Ischemia: Novel insights, Updated Mechanisms, and Implications for Myocardial Infarction.

Cannabis is the most widely trafficked and abused illicit drug due to its calming psychoactive properties. It has been increasingly recognized as having potential health benefits and relatively less adverse health effects as compared to other illicit drugs; however, growing evidence clearly indicates that cannabis is associated with considerable adverse cardiovascular events. Recent studies have linked cannabis use to myocardial infarction (MI); yet, very little is known about the underlying mechanisms. A MI is a cardiovascular disease characterized by a mismatch in the oxygen supply and demand of the heart, resulting in ischemia and subsequent necrosis of the myocardium. Since cannabis is increasingly being considered a risk factor for MI, there is a growing need for better appreciating its potential health benefits and consequences. Here, we discuss the cellular mechanisms of cannabis that lead to an increased risk of MI. We provide a thorough and critical analysis of cannabinoids' actions, which include modulation of adipocyte biology, regional fat distribution, and atherosclerosis, as well as precipitation of hemodynamic stressors relevant in the setting of a MI. By critically dissecting the modulation of signaling pathways in multiple cell types, this paper highlights the mechanisms through which cannabis may trigger life-threatening cardiovascular events. This then provides a framework for future pharmacological studies which can identify targets or develop drugs that modulate cannabis' effects on the cardiovascular system as well as other organ systems. Cannabis' impact on the autonomic outflow, vascular smooth muscle cells, myocardium, cortisol levels and other hemodynamic changes are also mechanistically reviewed.

Knowledge, attitude and practices related to COVID-19 among young Lebanese population.

BACKGROUND: As the world faces the most serious and widespread pandemic in recent history, claiming nearly 1,945,610 lives and infecting over 90 million individuals up to January 13, 2021, controlling the spread of COVID-19 is still limited to efforts done by the general population implementing rules and restrictions passed by world governments and organizations. As we wait for the approved vaccines to become widely distributed, the best approach to fighting the spread of this disease is mostly preventative depending largely on individuals' compliance. This study aimed to determine the knowledge, attitude and practices (KAP) towards COVID-19 in Lebanon. METHODS: A descriptive analysis was performed to describe the outcome measures of knowledge, attitudes and practices towards COVID-19 on a convenience sample from the Lebanese population in relation to socio-demographic characteristics and level of concern towards COVID-19. One thousand eight hundred sixty-one participants filled in an online survey (response rate: 18.5%) distributed by social media to social networks of the research team members. RESULTS: Participants were mainly young (49.4% between 18 and 24 years) and males (73.7%). Participants showed an overall appropriate knowledge of COVID-19 (67.1%) and positive attitude (around 90% were optimistic about treatment and vaccination) and had good preventive practices towards COVID-19 (around 75% washed hands and avoided public places). Knowledge and practices correlated positively with marriage, age, education, working in a healthcare field and with the level of concern about getting COVID-19. CONCLUSIONS: This study found good overall levels of KAP among the studied Lebanese population. This can help in controlling the spread of COVID-19 if individuals were forced to adhere to social distancing and appropriate preventative practices.

Inflammatory Basis of Atherosclerosis: Modulation by Sex Hormones.

Atherosclerosis-related cardiovascular diseases (CVDs) are the leading cause of death globally. Several lines of evidence are supportive of the contributory role of vascular inflammation in atherosclerosis. Diverse immune cell types, including monocytes/macrophages, T-cells and neutrophils, as well as specialized proresolving lipid mediators, have been successfully characterized as key players in vascular inflammation. The increased prevalence of atherosclerotic CVD in men in comparison to age-matched premenopausal women and the abolition of sex differences in prevalence during menopause strongly suggest a pivotal role of sex hormones in the development of CVD. Indeed, many animal and human studies conclusively implicate sex hormones as a crucial component in driving the immune response. This is further corroborated by the effective identification of sex hormone receptors in vascular endothelial cells, vascular smooth muscle cells and immune cells. Collectively, these findings suggest a cellular communication between sex hormones and vascular or immune cells underlying the vascular inflammation in atherosclerosis. The aim of this review is to provide an overview of vascular inflammation as a causal cue underlying atherosclerotic CVDs within the context of the modulatory effects of sex hormones. Moreover, the cellular and molecular signaling pathways underlying the sex hormones- immune system interactions as potential culprits for vascular inflammation are highlighted with detailed and critical discussion. Finally, the review concludes by speculations on the potential sex-related efficacy of currently available immunotherapies in mitigating vascular inflammation. Conceivably, a deeper understanding of the immunoregulatory influence of sex hormones on vascular inflammation-mediated atherosclerosis permits sex-based management of atherosclerosis-related CVDs.

Antibiotic use and resistance: an unprecedented assessment of university students' knowledge, attitude and practices (KAP) in Lebanon.

BACKGROUND: The emergence and spread of pathogenic bacteria that is resistant to antibiotics has become a major public health concern. The incorrect prescription, inappropriate consumption and excess use of antimicrobial drugs, specifically antibiotics, are possibly the main factors contributing to the widespread of antibiotic resistant bacteria. This study aims to evaluate the knowledge, attitude and practices (KAP) towards the use of antibiotics as well as their resistance among Lebanese university students in health and non-health related majors. METHODS: This cross-sectional study was conducted between May and June 2019 in Beirut (Lebanon) in which 750 students completed a questionnaire made up of four dimensions: Socio-demographic characteristics, 3 questions; assessment of knowledge, attitude and practices, 7, 10 and 1 question, respectively. The data was collected in spreadsheets and analysed with descriptive statistics. The difference in mean scores in each of the knowledge, attitude and practices dimensions between health and non-health related major students was analysed using t-student tests and the difference in percentages using chi-square tests. RESULTS: Almost 78% of respondents from the health related majors scored high knowledge compared to only 41% of non-health related majors (mean = 4.26; standard error = 0.05 versus mean = 3.41; standard error = 0.13, respectively). The attitude score of the health related major students (35.42%) was positive and more satisfactory compared to the non-health related students (7.32%); (mean = 9.34; standard error = 0.05 versus mean = 9.10; standard error = 0.21, respectively). However, the difference in the scores of attitudes was not statistically significant. CONCLUSIONS: Interventions to promote awareness in this area should focus more students in on non-health related majors.

Receptor protein tyrosine phosphatase sigma regulates synapse structure, function and plasticity.

The mechanisms that regulate synapse formation and maintenance are incompletely understood. In particular, relatively few inhibitors of synapse formation have been identified. Receptor protein tyrosine phosphatase σ (RPTPσ), a transmembrane tyrosine phosphatase, is widely expressed by neurons in developing and mature mammalian brain, and functions as a receptor for chondroitin sulfate proteoglycans that inhibits axon regeneration following injury. In this study, we address RPTPσ function in the mature brain. We demonstrate increased axon collateral branching in the hippocampus of RPTPσ null mice during normal aging or following chemically induced seizure, indicating that RPTPσ maintains neural circuitry by inhibiting axonal branching. Previous studies demonstrated a role for pre-synaptic RPTPσ promoting synaptic differentiation during development; however, subcellular fractionation revealed enrichment of RPTPσ in post-synaptic densities. We report that neurons lacking RPTPσ have an increased density of pre-synaptic varicosities in vitro and increased dendritic spine density and length in vivo. RPTPσ knockouts exhibit an increased frequency of miniature excitatory post-synaptic currents, and greater paired-pulse facilitation, consistent with increased synapse density but reduced synaptic efficiency. Furthermore, RPTPσ nulls exhibit reduced long-term potentiation and enhanced novel object recognition memory. We conclude that RPTPσ limits synapse number and regulates synapse structure and function in the mature CNS.

Cholinergic suppression of excitatory synaptic responses in layer II of the medial entorhinal cortex.

Theta-frequency (4-12 Hz) electroencephalographic activity is thought to play a role in mechanisms mediating sensory and mnemonic processing in the entorhinal cortex and hippocampus, but the effects of acetylcholine on excitatory synaptic inputs to the entorhinal cortex are not well understood. Field excitatory postsynaptic potentials (fEPSPs) evoked by stimulation of the piriform (olfactory) cortex were recorded in the medial entorhinal cortex during behaviors associated with theta activity (active mobility) and were compared with those recorded during nontheta behaviors (awake immobility and slow wave sleep). Synaptic responses were smaller during behavioral activity than during awake immobility and sleep, and responses recorded during movement were largest during the negative phase of the theta rhythm. Systemic administration of cholinergic agonists reduced the amplitude of fEPSPs, and the muscarinic receptor blocker scopolamine strongly enhanced fEPSPs, suggesting that the theta-related suppression of fEPSPs is mediated in part by cholinergic inputs. The reduction in fEPSPs was investigated using in vitro intracellular recordings of EPSPs in Layer II neurons evoked by stimulation of Layer I afferents. Constant bath application of the muscarinic agonist carbachol depolarized membrane potential and suppressed EPSP amplitude in Layer II neurons. The suppression of EPSPs was not associated with a substantial change in input resistance, and could not be accounted for by a depolarization-induced reduction in driving force on the EPSP. The GABA(A) receptor-blocker bicuculline (50 microM) did not prevent the cholinergic suppression of EPSPs, suggesting that the suppression is not dependent on inhibitory mechanisms. Paired-pulse facilitation of field and intracellular EPSPs were enhanced by carbachol, indicating that the suppression is likely due to inhibition of presynaptic glutamate release. These results indicate that, in addition to well known effects on postsynaptic conductances that increase cellular excitability, cholinergic activation in the entorhinal cortex results in a strong reduction in strength of excitatory synaptic inputs from the piriform cortex.

Visualization of the dendritic arbor of neurons in intact 500 microm thick brain slices.

Characterizing the structure and electrophysiological properties of single neurons is essential for understanding how individual cells contribute to the function of neuronal networks. Following intra-cellular recording from neurons in acute brain slices, the structure of the recorded cell has typically been examined by serial sectioning of the tissue slice and then reconstructing the neuron of interest; a labor-intensive and time-consuming process. Here, we have adapted a whole-mount immunohistochemical technique and used it to visualize the dendritic arbor of individual neurons in sections of adult CNS tissue up to 500 microm thick. Permeabilization of the slice and extensive washing allow histochemical reagents to penetrate and be washed from the section, producing limited background staining. Using this method, the cell within the slice can be sectioned optically and reconstructed using the optical sections. We present images of the dendritic trees of neurons in 500 microm thick slices of adult rat entorhinal cortex and hippocampus, labeled either immunohistochemically, or by biocytin injection following whole-cell patch clamp or sharp electrode recordings. The resolution obtained is sufficient to visualize dendritic spines deep within the section. The method is free from artifacts associated with cutting serial sections and is broadly applicable to tasks that require visualization of the fine structure of individual cells in thick slices of CNS tissue.

Graded persistent activity in entorhinal cortex neurons.

Working memory represents the ability of the brain to hold externally or internally driven information for relatively short periods of time. Persistent neuronal activity is the elementary process underlying working memory but its cellular basis remains unknown. The most widely accepted hypothesis is that persistent activity is based on synaptic reverberations in recurrent circuits. The entorhinal cortex in the parahippocampal region is crucially involved in the acquisition, consolidation and retrieval of long-term memory traces for which working memory operations are essential. Here we show that individual neurons from layer V of the entorhinal cortex-which link the hippocampus to extensive cortical regions-respond to consecutive stimuli with graded changes in firing frequency that remain stable after each stimulus presentation. In addition, the sustained levels of firing frequency can be either increased or decreased in an input-specific manner. This firing behaviour displays robustness to distractors; it is linked to cholinergic muscarinic receptor activation, and relies on activity-dependent changes of a Ca2+-sensitive cationic current. Such an intrinsic neuronal ability to generate graded persistent activity constitutes an elementary mechanism for working memory.

Morphological and electrophysiological characteristics of layer V neurons of the rat lateral entorhinal cortex.

The intrinsic electrophysiological and morphological properties of lateral entorhinal area (LEA) layer V neurons were investigated by sharp electrode intracellular recording and biocytin labeling in vitro. The morphological analysis revealed that layer V of the LEA contains three distinct subtypes of principal neurons, which were classified as pyramidal, horizontal, and polymorphic neurons. Pyramidal cells were the most abundant subtype (57%) and could be further subdivided into neurons with large, small, and star-like somas. Similarly to pyramidal cells, horizontal neurons (11%) had a prominent apical dendrite. However, their distinctive basal dendritic plexus extended primarily in the horizontal plane. Polymorphic neurons (32%) were characterized by a multipolar dendritic organization. Electrophysiological analysis of neurons in the three categories demonstrated a diversity of electrophysiological profiles within each category and no significant differences between groups. Neurons in the three subgroups could display instantaneous and/or time-dependent inward rectification and different degrees of spike frequency adaptation. None of the recorded cells displayed an intrinsic oscillatory bursting discharge. Many neurons in the three subgroups, however, displayed slow (3.5-14 Hz), sustained, subthreshold membrane potential oscillations. The morphological and electrophysiological diversity of principal neurons in the LEA parallels that previously reported for the medial entorhinal area and suggests that, with respect to the deep layers, similar information processing is performed across the mediolateral extent of the entorhinal cortex. Layer V of the entorhinal cortex may undertake very complex operations beyond acting as a relay station of hippocampal processed information to the neocortex.